回一位朋友关于绿卡问题的悄悄话

有朋友在悄悄话里给费某提了个问题。费某回了。但是似乎该朋友没读。为使费某不至于白费力气，就贴在这里，希望能被看到。

如申请公民,是否过去的5年,每年至少要在美呆半年以上?
If no exception applies, the answer is yes.

时间上怎么计算?
During the five years immediately prior to filing the petition for naturalization the applicant shall have been physically present in the US for at least half of the time.
This is the totality calculation. However you should be aware of limitation of the 6 months oversea stay.

可以出境3个月,然后必须在美呆3个月吗?
Not necessary. Please see the above two methods to calculate.